The Bio-AFM facility was installed in January 2014, in the department of “Bio-Science & Bio-Engineering” Central Facility as per RIFC norms. The Facility is open for all IIT Bombay internal users, other institutes, National Laboratory, and Industry.
The principle of operation of the AFM is very simple - A sharp cantilever tip interacts with the sample surface sensing the local forces between the molecules of the tip and sample surface. This instrument is not a “conventional microscope” that collects and focuses light. The word microscope has been associated with this instrument because it is able to measure microscopic features of the sample. The most characteristic property of the AFM is that the images are acquired by “feeling” the sample surface without using light. In this way, not only the sample topography can be recorded with good resolution, but also the material characteristics and the strength of interaction between the sample surface and the cantilever tip. Due to the fact that no light is involved in acquiring the sample properties, the AFM reaches a resolution far below the diffraction limit offered by the optical microscopy. Its resolution is limited only by the tip radius and the spring constant of the cantilever.

Features

• High-Resolution imaging in liquid for soft biological samples.
• No pre-processing of materials/cells is required for imaging.
• Ability to combine AFM measurements with images obtained in an inverted microscope.
• Real-time Optical Navigation: Top or bottom-view optical images can be used to navigate the tip to any feature on the sample and then scan that area at the nanoscale with the AFM or select specific locations for force curves - easily and seamlessly.
• Powerful Real-time and Offline Rendering Options: Both AFM and optical images can be rendered and viewed together in both real-time and offline. Optical images can be overlaid on AFM data to assist interpretation. Stunning 3D renderings combine AFM topography with the capabilities of light microscopy.

Supported Optical Techniques

• Bright-field
• Phase Contrast
• Fluorescence
• Large Z range (40 μm extended Z) accommodates demanding applications such as cell-cell and cell-substrate adhesion measurements.
• Users can choose between open loop force curves with sensored Z for the ultimate in low noise performance or closed loop Z for the most accurate velocity control.
• Force Mapping measures force-distance curves at a grid of points with automated fitting of indentation models for estimation of elastic modulus and automated adhesion/rupture force analysis.
• Analysis software helps by suggesting the most appropriate indentation model among many built-in options, including "Hertz / Sneddon, Johnson-Kendall-Roberts (JKR), Derjaguin-Muller-Toporov (DMT), and Oliver-Pharr", or students may also freely enter their customized models.